A marked advantage of the radar reflector according to the invention is that it can be folded up into a flat pack having a very small intrinsic volume, and that it can be stored in this state until deployed, whereupon it will be automatically unfolded, without the need for special opening elements, into a corner reflector of tried and tested design. The basic design of the radar reflector according to the invention is therefore previously known and it has the marked advantage that in its free flight it will tumble through the atmosphere and by virtue of its specific design will always create a dummy target, which although it may pulsate, will always be present.
The radar reflector according to the invention is therefore of the corner reflector type and is produced by bending and joining together an essentially plane radar wave-reflecting sheet material. By selecting a sheet material having a suitable shape memory for its manufacture, ingenious folding allows the radar reflector according to the invention to be made so that it can be folded up very compactly. At the same time, as soon as it leaves the packaging or the storage container keeping it in the folded state, it will automatically unfold to the desired shape without any separate opening elements whatsoever.
As already intimated, the radar reflector according to the invention in its open state has a thoroughly tried and tested basic shape, the good characteristics of which are well-known. This basic shape, which essentially comprises a square base plane bounded by four edge sides, along which the sheet material from which it is constructed is bent upwards or downwards relative to the extent of the base plane, this bending being done in the same direction on two of these adjoining edge sides and in the opposite direction along two opposing edge sides, said bends with the reflector in its opened state being made essentially at right-angles to the base plane and the sheet material along each such edge side continuing in the form of an essentially square reflector surface, whose own edge sides, in addition to the edge side along which the bending has been performed, constitute closing edges for the sheet material in the reflector, and adjoining closing edges of the edge material in said reflector surfaces bent upwards or downwards in the same direction being joined to one another along said adjoining closing edges, so that the reflector surfaces included therein together form a corner reflector.
Radar reflectors of this basic type are described in U.S. Pat. No. 3,138,798. This patent specification not only describes its good radar-reflecting characteristics and the advantages of its tumbling about in free flight in a manner advantageous for the radar wave reflection, but also notes that multiple such reflectors can in fact be nested one inside another, which means that it is possible to limit the volume occupied by a number of these reflectors nested one inside another. In addition, it also proposes that by rounding the exposed corners of the reflector surfaces it should be possible to accommodate a plurality of such nested reflectors in a spherical container capable of opening by dropping, which would thereby at the same time permit cluster dropping of a plurality of reflectors. Although the nesting and insertion of multiple reflectors in spherical containers described in the patent specification has certain advantages, this type of packing implies a requirement for large, empty spaces available in the carrier from which the reflectors are intended to be deployed.